Oliveira, M.F. and Marenco, R.A.
2019
"Photosynthesis and biomass
accumulation in Carapa
surinamensis (Meliaceae)
in response to water stress
at ambient and elevated CO2."
Photosynthetica 57: 137-146.
NOTE:
Climate models predict portions
of the Amazon will have problems
with droughts in the future.
The impact of such predictions
on the growth of tropical trees
has not been thoroughly examined.
SUMMARY:
The authors say:
"elevated CO2 conditions
negated the effect
"elevated CO2 conditions
negated the effect
of water stress
on light-saturated
on light-saturated
net photosynthesis"
and also
and also
"mitigated the effect
of water stress
on biomass
accumulation."
accumulation."
These findings show the ability
of Carapa to "endure drought
or to improve carbon uptake
at elevated CO2 conditions."
DETAILS:
Drought reduced the
net photosynthetic rate
by +33.5% at ambient CO2
conditions.
Elevated CO2 increased
this rate by +64% and +152%
when soil water capacity
was maintained at 100%
and 50%, respectively.
Drought also negatively
impacted plant biomass,
but elevated CO2 had a
positive effect -- a +24%
increase at 100% soil water
capacity and a larger +40%
increase at 50% soil water
capacity.
Oliveira and Marenco (2019)
grew andiroba trees
( Carapa surinamensis )
under two CO2 concentrations
and two watering regimes
over a period of 163 days.
This was done in controlled
environments at the National
Institute for Research
in the Amazon in Manaus, Brazil.
Atmospheric CO2 concentrations
were 400 or 700 ppm and the two
watering regimes represented
well-watered soil ( kept at 100%
field capacity ) and drought
( soil kept at 50% field capacity ).
